I have previously devised novel and improved scissor frame hoists employed on dump trucks for the purpose of stabilizing the movement of the dump body as it is elevated and tilted rearwardly by a hydraulic cylinder lift mechanism. For example, reference is made to U.S. Pat. Nos. 3,809,429; 4,148,528; and 4,592,593.
For light duty trucks (15,000 lbs. and under gross vehicle weight), the conventional hoist normally used is a drop-hinge scissor hoist in which the scissor hinge of the hoist is dropped down below the top surface of the truck frame and positioned between the truck frame side rails or long members. A typical example of a drop-hinge scissor hoist is the Low Profile LP-090 manufactured by Hydraulics Unlimited Manufacturing Co. of Eaton, Colo. In the LP-090, as well as the other typical drop-hinge scissor hoists, the scissor hinge is the full width of the hoist frame. Inasmuch as the upper and lower scissor frames operate at high stress levels, it is an advantage to have those frames disposed as straight as possible so that forces can be carried directly therethrough without having to "bend the forces around corners."
Very recently, truck chassis manufacturers have been leaving less and less room available between the frame members for the scissor hinge of the hoist. This is due in large amount to the encroachment of exhaust pipes, fuel tanks, brake equalizer valve linkages, and various brackets into the area of the hoist scissor hinge. In some cases, it is impossible to install a conventional drop-hinge scissor hoist because of interference with those components.
It is therefore a principal object of this invention to provide an improved scissor frame lift apparatus for dump trucks.
Yet another object of the invention is to provide a drop-hinge scissor frame lift apparatus for dump trucks wherein the scissor hinge is not "full width" but has a width substantially less than the distance between the truck frame members.
Yet another object of the invention is to provide a scissor frame lift apparatus including a narrow scissor hinge which permits the installation of the same on some trucks which would otherwise be unable to accommodate conventional drop-hinge scissor hoists.
Yet another object of the invention is to provide a scissor frame lift apparatus for dump trucks including a narrow scissor hinge which reduces the amount of time required for mounting the body and hoist on a truck.
Yet another object of the invention is to provide a scissor frame lift apparatus of the type described which reduces the mounting costs thereof.
A further object of the invention is to provide a scissor frame lift apparatus of the type described which permits the hoist to be mounted on different sizes and types of equipment.
Yet another object of the invention is to provide an incorporated body prop which does not load the scissor frame during prop function.
Still another object of the invention is to provide a scissor frame lift apparatus of the type described which is economical of manufacture, durable in use and refined in appearance.
These and other objects of the present invention will be apparent to those skilled in the art.